Shower arm



FIG. 1 is a perspective view of a shower arm showing our design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof; the right side elevational view being a mirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines in the drawings represent unclaimed portions of the design and form no part thereof. 

The ornamental design for a shower arm, as shown and described. 